The Oakland Athletics released right-handed reliever Santiago Casilla on Thursday, five days after he was designated for assignment.

Casilla, who turns 38 on Wednesday, had a 3.16 ERA in 26 appearances this season, but he had struggled with his command. He walked 20 batters, hit four more and threw four wild pitches in 31 1/3 innings of work.

In his 15th MLB season, Casilla was two years into his second stint with the A’s, with whom he spent the first six years of his career.

He is 42-31 with a 3.29 ERA in 655 career games, all in relief with the A’s and San Francisco Giants.